In a general aspect thereof the present invention relates to a wheel for vehicles.
More particularly, the invention relates to a wheel for vehicles which has a preferred, although non-exclusive use, both on high or very high performance cars, so-called HP (High Performance) or UHP (Ultra High Performance) and on heavy vehicles adapted, for example, to cover long travels in motorways or for heavy uses.
As is known, in a wheel for vehicles, whatever its final application, the tyre is coupled to the rim by means of the interaction between its radially inner end portions, the so-called beads, and the rim itself.
More particularly, the rim comprises in the tyre coupling zone a pair of axially outer flanges extending at least in part along a radial direction and delimiting respective bead housing seats circumferentially extending at an axially inner position with respect to the flanges. These bead housing seats are provided in turn with a base portion and a side portion adapted to cooperate in an abutting relationship with the base and, respectively, with a side portion of the respective bead.
In the case of tyres for a high (HP) or a very high (UHP) performance car, including sporting uses, or in the case of tyres subjected to very high axial and radial loads, as in the case of tyres for heavy vehicles, problems often arise due to the interaction between the rim and the tyre and particularly due to the relative movement between the two elements. Due to very high circumferential and transversal stresses, in fact, tyre movements can occur during use both along a circumferential direction and along an axial direction with respect to the respective rim on which the tyre is mounted, giving rise to a phenomenon known in the art with the term of “bead setting”.
In the case, for example, of high driving torques suddenly delivered in acceleration, it may occur that the tyre tends to slide with respect to the rim with a relative rotation along the circumferential direction which is not normally balanced by an identical rotation of the other tyre arranged on the same axle, which relative rotation may impart a rather dangerous drift movement to the vehicle, as it can be sudden and thus not very controllable.
On the other hand, in the case of severe and repeated transversal accelerations of the vehicle, typically related to curves covered at high speed, undesired axial movements of the tyre bead with respect to its housing seat formed in the rim on which the bead was installed during mounting may gradually arise.
The same undesired effect can be produced not only by a strong transversal acceleration, but also by a high transfer of transversal load, such as for example in the case of heavy vehicles.
These movements along the axial direction cause a geometric configuration at the interface between the tyre and the rim which is different from the design one, with a consequent irregular transmission of forces between the wheel and the vehicle and an increasingly deteriorated vehicle behaviour, particularly as far as lateral stability and handling are concerned.